The present invention relates to the sheet-like member holding device of a printing press for holding a sheet-like member disposed on the outer surface of the cylinder of the printing press.
Conventionally, a sheet-like member is often attached to the surface of a printing cylinder, as disclosed in Japanese Patent Laid-Open Nos. 3-286866 (literature 1) and 3-286867 (literature 2). The sheet-like member disclosed in literatures 1 and 2 is a protection sheet. This protection sheet covers a sheet support portion for supporting a sheet on the printing cylinder. The protection sheet disclosed in literatures 1 and 2 is fixed to the printing cylinder by a protection sheet holding device.
The protection sheet holding device disclosed in literatures 1 and 2 is disposed in an gap formed in an outer surface of the printing cylinder. A gripper device for gripping and holding a sheet is disposed in the gap. The gripper device sandwiches and holds a sheet by a gripper and a gripper pad. The protection sheet holding device adopts an arrangement of holding one end portion of the protection sheet using a sheet holding member disposed inside the gripper pad of the gripper device in the radial direction of the printing cylinder. The other end portion of the protection sheet is wound around a sheet holding shaft disposed in the gap, and held.
The above-described sheet holding member is disposed at a position opposing a side wall extending in the radial direction of the printing cylinder in the gap to be movable forward and backward, and sandwiches one end portion of the protection sheet in cooperation with the side wall. The gripper pad is configured to contact or be separated from the above-described side wall. When making the sheet holding member hold one end portion of the protection sheet, the gripper pad is separated from the side wall to form, between the gripper pad and the side wall, a space through which the protection sheet passes. When the gripper pad moves, the gripper swings to a release position to avoid interference with the gripper pad.
As described above, in the protection sheet holding device disclosed in literatures 1 and 2, when attaching the protection sheet to the printing cylinder, it is necessary to move the gripper and the gripper pad. This operation not only imposes a load on an operator but also causes a failure of the gripper, or misregistration or a failure of the gripper pad.